This Scientific Program in the proposed CETR addresses the discovery and development of bacterially produced molecules that could become therapeutic agents to provide new antifungal and antibacterial agents to address the growing challenge to human health posed by resistant microbial pathogens. The emphasis on bacterially produced molecules is partly historical - most of our useful antifungal and antibacterial agents are, or were derived from, bacterially produced molecules - and partly ecological - the bacteria being investigated are symbionts on higher organisms and are known, or likely, producers of antimicrobials. This overall goal is based on three specific aims: Specific Aim 1: Explore symbiotic environmental niches and taxa for the production of novel compounds with antimicrobial activity against drug resistant target fungi and bacteria. This project will focus largely on Proteobacteria that have been isolated from symbiotic environments. Strains will be prioritized by phylogenetic novelty as measured by 16S sequencing. Specific Aim 2: Develop robust methods to identify novel natural products with antimicrobial activity against drug resistant target fungi and bacteria. Selected strains will be examined for biosynthetic potential through techniques such as culturing, co-culturing, genome sequencing, elicitors, and heterologous expression. Specific Aim 3: Identify combinations of symbiotic environments, taxa, and biological assays that most efficiently discovery safe and effective lead antimicrobials. Compounds with high activity levels in the screening cores, will be further examined. Production will be optimized, semi-synthetic derivatives will be prepared, and efforts to identify mechanism of action begun.